No need to upgrade. The 6870 and 6850 perform slightly worse than the 5870, but they are cheaper. But the 69** series haven't been unveiled yet, and obviously they will out-perform the 5870, but I would assume the price being quite high. If I were you, I would stick with the 5870 for a while, and if you are really itching for a few extra FPS, just get another 5870.